Maximum-minimum governor device



MarchlO, 1970 J. M. BAILEY MAXIMUM-MINIMUM GOVERNOR DEVICE Filed May 29, 1968 Eillu INVENTOR JOHN M. BAILEY ATTORNEYS United States Patent 3,499,426 MAXIMUM-MINIMUM GOVERNOR DEVICE John M. Bailey, Dunlap, Ill., assignor to Caterpillar Tractor Co., Peoria, Ill., a corporation of Illinois Filed May 29, 1968, Ser. No. 733,134 Int. Cl. F02d 1/04 US. Cl. 123140 1 Claim ABSTRACT OF THE DISCLOSURE A hydro-mechanical governor in which a cup shaped spring seat has mounted therein a sleeve biased to an extended position. The spring seat and sleeve construction is biased away from an adapter actuated by centrifugal flyweights. The construction allows the engine operator to control the fuel pump rack within the operating range while still having a governed low idle and maximum speed.

This invention relates to an improvement in a double acting hydraulic servo governor such as that shown in US. Patent No. 3,145,624 to Parks et al., and assigned to the assignee hereof. More specifically, the invention relates to a spring biased spring seat member having, effectively, a lost motion capability therein. The addition of the lost motion capability serves to convert the governor from a full range governor as disclosed in Parks et al. to a maximum-minimum fuel control governor. This arangement provides a vehicle operator with a means for directly controlling the fuel pump rack of an engine throughout the operating range while still having a governed low idle and maximum speed.

Of primary concern when using conventional, mechanical, or hydraulically assisted governors in highway vehicles, is the lack of positive control of the fuel pump rack by the operator. The use of a governor wherein a control lever adjusts a spring which interacts with fiyweights to obtain governed speeds is well known as shown in the above cited patent. In such a device, the speed selected by the operator is regulated by compression or extension of the governor spring by the control lever. This is a highly desirable feature in industrial applications such as generator engines, etc., wherein it is desired that the governor control the fuel input to the engine throughout the full range of engine power output. However, this is not desirable when the engine is utilized in an application such as a truck drive system wherein the operators foot must counteract the force of the fiyweights at all time. In such cases, the spring would always be in the mechanical control circuit. In foot actuated accelerator linkage, this action transmits a spongy effect to the operator through the accelerator linkage.

A further disadvantage of such structure is that a small movement of the fuel pump rack is obtained only through a much larger movement of the control lever and spring.

In those governors presently known, another problem encountered is that excessive flyweight forces are transmitted from the governor to the accelerator linkage during engine operation. Obviously, the higher the engine speed the more force transmitted to the accelerator linkage, and the greater the effort on the part of the engine operator.

It is therefore an object of the present invention to provide a hydro-mechanical governor which produces a high quality of engine control with fuel injection governing at low idle speed and maximum speed.

It is an object of this invention to provide such a governor having a reduced stress creating effect on the accelerator linkage.

It is also an object of this invention to provide such a governor having a suitably firm feel to the operator,

3,499,426 Patented Mar. 10, 1970 p CC while requiring a lesser effort on his part to maintain desired engine speed.

Further and more specific objects and advantages of the invention will become apparent upon reading the following specification wherein a preferred embodiment of the invention is described byreference to the accompanying drawing.

In the drawing:

FIGURE 1 is a side elevation sectional view of the governor of the present invention with parts broken away as necessary.

FIGURE 2 is a view similar to FIGURE 1, showing a portion of the invention with certain parts in a different position.

Referring to the drawing, a governor 11 has a bifurcated control lever 13 which engages a cup-shaped spring seat 15 that is slidable on a support member 17. When lever 13 is rotated counter clockwise, the spring seat 15 is urged to the right, as shown in the drawing, tending to compress or load a governor spring 19. The entire spring seat assembly acts upon an adapter 21 which is restricted in its movement to the right by a rod 23 having a shoulder 25 engaging a complementary shoulder 27 on the adapter. Rod 23 is limited in its rightward movement by retainer 29 which abuts a stop 31.

A spring 33 extends between a shoulder 35 of a sleeve 36 and the adapter 21. Sleeve 36 is telescopically axially slidable within spring retaining member 15 and is biased toward an extended position by the spring 19 wherein it is retained by a ring 37. Since spring 19 is preloaded within retainer 15, the low idle spring 33 tends to force sleeve 36, spring 19, and retainer 15 to the left as shown in the drawing.

To increase engine speed, lever 13 is moved in a counter clockwise direction against spring retainer 15. This tends to compress spring 33, thereby urging adapter 21 rightwardly against the force of flyweights 69.

As described in the above cited patent to Parks et al., rightward movement of adapter 21 causes a movement to the right of fuel pump rack 67 in the following manner. Oil is supplied to the valve 49 through an oil supply passage 51 which communicates with a passage 53 in the cylinder 55. The oil then flows through a passage 57 to an annulus 59 in the spool 48 and from there to a passage 61 in a piston 63 and into chamber 65. When the oil pressure in chamber 65 becomes great" enough, piston 63 will move to the right and urge a fuel pump rack 67 in the same direction thereby increasing engine speed. Continued movement of lever 13 in a counter clockwise direction causes the compression of spring 33 until a face 39 of sleeve 36 abuts the adapter 21 at a face 40 thereof as shown in FIGURE 2. Due to the movement of the lever 13 in the counterclockwise direction in response to a signal from the operator, the governor spring 19 will maintain the relative position of the sleeve 36 and cupshaped member 15 throughout the normal operating speed range of the engine. Proper selection of the generator spring will allow the spring to act to hold the member 15 and sleeve 36 as far apart as possible throughout this range. However, when the engine tends to run at a speed greater than the maximum speed of its operating range, the amount of force generated by the lever 13 and the flyweight 69 will be such as to cause the spring 19 to begin to compress and act to oppose the over-speed in the known manner.

In a decrease in engine speed lever 13 is rotated in a clockwise direction as shown in the drawing.'This allows the flyweight 69 to move out radially, urging adapter 21 and valve spool 48 to the left blocking the oil supply passage 57, allowing oil in cavity 65 to escape through passage 61, around a groove 71, and out a passage 73. The dumping of the oil allows adapter 21 to pull rack 3 67 leftwardly, thereby decerasing the volume of fuel being injected into the engine.

When lever 13 is set in a 10W idle position, flyweights 69 move radially under the influence of engine speed to urge adapter 21 against the opposiing force of low idle spring 33. The axial movement of adapter 21 adjusts the fuel pump rack 67 to its low idle position through the servo system described above. When the opposing force of spring 33 balances the forces acting against flyweights 69, a low idle speed is obtained.

Thus, low idle speed is governed through the use of spring 33 and a maximum speed is governed through the use of governor spring 19. Should engine speed become greater than the maximum safe limit, the force acting upon flyweights 69 moves adapter 21 leftwardly from a position shown in FIGURE 2 upon spring 19 through the direct contact of sleeve 36 with the adapter. As adapter 21 moves to the left, rack 67 is moved to reduce the volume of fuel injected into the engine thereby decreasing engine speed. When a safe engine speed is reached, the force of spring 19 is sufiicient to return sleeve 36 to its operational range setting against ring 37.

Thus, the applicant has provided a means to permit the operator of a highway vehicle direct control of the fuel pump rack in the operating speed range of the engine while governing the idle and maximum speeds. This is accomplished by preloading spring 19 and retaining it in a set position throughout the operating speed range. Because spring 19 acts as a solid member throughout this range, direct contact is maintained with the adapter 21 by sleeve 36, allowing the operator direct control of rack 67 without experiencing the spongy effect of the spring. Eliminating use of the spring in the operating range permits a shorter movement of the governor lever to obtain a corresponding movement of the fuel pump rack. Thus a large portion of the operating range is removed from the governor. Use of suitable linkage between the accelerator and the governor lever will provide suitable mechanical advantage such that only reduced forces can be transmitted from the governor to the accelerator thus minimizing operator fatigue.

What is claimed is:

1. An engine governor for controlling the maximum and minimum speeds at which an engine can run While allowing direct operator control of the fuel delivered to the engine between said maximum and minimum speeds comprising:

a fuel control member,

an adapter member,

an hydraulic servo means operatively connected to said fuel control member and to said adapter member,

a set of flyweights driven by the engine and bearing on said adapter member to tend to motivate said servo means and said fuel control member to a decreased fuel input position,

a sleeve member movably mounted adjacent said adapter and having a flange thereon,

a first spring positioned for compression between said adapter member and said flange to a position causing abutment of said adapter member and said sleeve member,

a spring seat slidably mounted relative to said sleeve member,

a second spring positioned for compression between said flange and said spring seat, and

fuel control linkage operatively connected to said spring seat for moving said fuel control member to an increased fuel input position via said spring seat, said second spring, said sleeve member, said adapter member, and said servo valve without loss of force through compression of said second spring when said first spring is compressed to allow said sleeve member to abut said adapter member.

References Cited UNITED STATES PATENTS 2,669,983 2/1954 Reddy et al. 123-140 2,727,503 12/1955 Reiners 123-140 3,145,624 8/1964 Parks et al. 123140 XR 3,426,739 2/1969 Bailey et al. 123-140 LAURENCE M. GOODRIDGE, Primary Examiner 

